Local Break Out (LBO) means that the service data used by the user in a roaming state are transmitted to the destination directly through the visited network, without need of being routed back to the home network from the visited network and then transmitted to the destination by the gateway of the home network. The LBO services are directly processed by the visited network, without need of using the routing between the home network and the visited network. In this way, good experience of the user can be ensured, and operation costs can be reduced by saving the bandwidth between networks of different operators.
The Policy and Charging Control (PCC) architecture used in the LBO scenario of the Evolved Packet System (EPS) of R8 defined by the current 3rd Generation Partnership Project (3GPP) wireless communication standard organization is as shown in FIG. 1.
An Application Function (AF) provides access points for service applications, and dynamic policy control needs to be performed on the network resources used by these services applications. When the service plane performs parameter negotiation, AF transmits related service information to a Policy and Charging Rules Function (PCRF). If this service information is consistent with the policy of the PCRF, then the PCRF accepts the negotiation; otherwise, the PCRF rejects the negotiation, and meanwhile provides service parameters acceptable to PCRF in the feedback. Subsequently, AF may return these parameters to User Equipments (UE). Wherein, the interface between AF and PCRF is an Rx interface.
A Policy and Charging Rules Function (PCRF) is a core of the PCC (the figure includes a home network PCRF(H-PCRF) and a V-PCRF(V-PCRF)), and is responsible for making policy decision and charging rules. The PCRF provides network control rules based on service data flow, and the network control includes detection of service data flow, Gating Control, Quality of Service (QoS) control and charging rules based on data flow. The PCRF transmits the policy and charging rules made by itself to a Policy and Control Enforcement Function (PCEF) for enforcement, and meanwhile the PCRF also needs to ensure the consistence between these rules and the user's subscription information. The basis for the PCRF mading policy and charging rules includes: obtaining information related with services from the AF; obtaining user policy charging control subscription information from Subscription Profile Repository (SPR); obtaining information of a network related with bearer from PCEF.
Policy and Control Enforcement Function (PCEF) is generally located inside a Gate Way (GW), and performs the policy and charging rules made by PCRF on the bearer plane. PCEF detects the service data flow according to the service data flow filter in the rules transmitted by the PCRF to perform the policy and charging rules made by the PCRF on the service data flow. When a bearer is established, PCEF performs QoS authorization according to the rules transmitted by PCRF, and performs gating control according to the performing of AF. PCEF implements the corresponding service data flow charging operation according to the charging rules transmitted by PCRF. Charging may be online charging, or offline charging. If it is online charging, then PCEF needs to implement credit management together with an Online Charging System (OCS). In the case of offline charging, PCEF and an Offline Charging System (OFCS) interchange related charging information. The interface between the PCEF and PCRF is a Gx interface, the interface with the OCS is a Gy interface, the interface with OFCS is a Gz interface. PCEF is generally located on a gateway of a network, for example, GPRS gateway support node (GGSN) in GPRS and Packet Data Gateway (PDG) in I-WLAN.
The functions of a Bearer Binding and Event Reporting Function (BBERF) include bearer binding, verification of uplink bearer binding and event report. When a UE accesses via an evolved universal terrestrial radio access network (E-UTRAN), and a proxy mobile IPv6 protocol (PMIPv6) is adopted between the serving gateway (S-GW) and Packet Data Network Gateway (P-GW), BBERF is located in the S-GW; when the UE accesses via a trusted non-3GPP access system, the BBERF is located in a trusted non-3GPP access gateway, and when the UE accesses via an un-trusted non-3GPP access system, the BBERF is located in the Evolved Packet Data Gateway (ePDG). In this case, the PCEF does not implement the bearer binding function.
A SPR stores user policy charging control subscription information related with policy control and charging. The interface between the SPR and PCRF is an Sp interface.
OCS, together with PCEF, implements control and management of user credit in the online charging manner.
OFCS, together with PCEF, implements charging operation in the offline charging manner.
In the LBO roaming scenario, the PCEF is located in a Visit Public Land Mobile Network (VPLMN), policy and charging rules are transmitted from the PCRF of the home network (i.e., H-PCRF) to the PCRF of the visited network (i.e., V-PCRF) via an S9 interface, and then are transmitted to the PCEF located in the visited network via a Gx interface, and transmitted to the BBERF located in the visited network via a Gxx interface. The PCEF of the visited network is connected to the OFCS of the visited network, and is connected to the OCS of the home network via a Gy interface.
With respect to the online charging problem in the LBO roaming scenario, there is still no deep study in the related technologies, and only a basic framework is proposed. As shown in FIG. 2, there is a visited network online charging system (V-OCS) in the visited network responsible for delivering the credit control policy delivered by a home network online charging system (H-OCS) to the PCEF of the visited network. Meanwhile, the online charging information reported by the PCEF is reported to the H-OCS.
It is required in the related technology that the policy and charging rules in the LBO roaming scenario are dominated by the home network PCRF (i.e., H-PCRF), credit management is controlled by the home network OCS (i.e., H-OCS). The user can only subscribe to roaming data services with a home network operator, and the subscription information about the user subscribing to roaming data services can only be stored in the home network. The user cannot further subscribe to roaming data services with a visited network operator using the SIM/USIM card and the Mobile Subscriber International ISDN number (MSISDN) assigned by the home network, wherein ISDN is an Integrated Services Digital Network. The local data services, roaming data services, and circuit domain services subscribed by the user cannot be split or provided by different operators. When quality of service or charging of the roaming data service provided by the home network operator is not competitive, the user may have to endure the roaming data services provided by it because the user still needs other services provided by the home network operator. The LBO roaming scenario made by the related technology cannot give full play to its advantages since policy and charging control and credit management are still dominated by the home network.